CMOS active pixel sensors (APS) incorporate either voltage- or current-mode readout. Voltage-mode readout has been in use since the first 3-transistor (3T) CMOS APS imager disclosed by Fossum, “CMOS image sensors: electronic camera-on-a-chip,” IEEE Trans. Electron. Devices, Vol. 44, No. 10, pp. 1689-1698, 1997, and is still the dominant choice of CMOS imagers in the market today (see, El Gamal, et al. “CMOS image sensors,” IEEE Circuits Devices Mag., Vol. 21, No. 3, pp. 6-20, 2005). Current-mode readout is used mostly to facilitate focal-plane image processing, because many analog computations can be easily done in the current domain as described, for example, by Gruev, et al., “Implementation of steerable spatiotemporal image filters on the focal plane,” IEEE Trans. Circuits Syst. II, Vol. 49, No. 4, pp. 233-244, 2002. Despite this advantage, most current-mode imagers suffer from higher noise level, or poorer image quality. An imager is desired that provides improved image quality while also facilitating focal-plane image processing. The present invention is provided to meet this need.